| Parameter |
Value |
| Designation |
442P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-08-20T19:07:02.740800Z |
| Orbit solution date (soln_date, UTC) |
2024-07-07T00:42:22Z |
| Obs used |
452 |
| NEO |
- |
| M1 |
10.500 |
| K1 |
19.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-08-20.0000000 |
| e |
0.53159899 |
| q (au) |
2.328281 |
| a (au) |
4.970701 |
| i (deg) |
6.053247 |
| Ω (om, deg) |
32.033725 |
| ω (w, deg) |
310.972640 |
| M (ma, deg) |
229.993643 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.717 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.717 |
| n |
2.000 |
| gf |
0.993 |
| gb |
-0.900 |
| k |
0.999 |
| δ90 |
1.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
09:12:02.51 |
+21:50:38.3 |
HIP 45046 |
23.85 |
| 2026-06-01 12:00 |
09:12:13.69 |
+21:49:27.6 |
HIP 45046 |
25.77 |
| 2026-06-02 00:00 |
09:12:24.95 |
+21:48:16.6 |
HIP 45046 |
27.87 |
| 2026-06-02 12:00 |
09:12:36.31 |
+21:47:05.2 |
HIP 45046 |
30.12 |
| 2026-06-03 00:00 |
09:12:47.77 |
+21:45:53.6 |
HIP 45272 |
31.11 |
| 2026-06-03 12:00 |
09:12:59.32 |
+21:44:41.6 |
HIP 45272 |
29.07 |
| 2026-06-04 00:00 |
09:13:10.96 |
+21:43:29.2 |
HIP 45272 |
27.19 |
| 2026-06-04 12:00 |
09:13:22.69 |
+21:42:16.6 |
HIP 45272 |
25.51 |
| 2026-06-05 00:00 |
09:13:34.52 |
+21:41:03.6 |
HIP 45272 |
24.07 |
| 2026-06-05 12:00 |
09:13:46.43 |
+21:39:50.3 |
HIP 45272 |
22.94 |
| 2026-06-06 00:00 |
09:13:58.44 |
+21:38:36.7 |
HIP 45272 |
22.17 |
| 2026-06-06 12:00 |
09:14:10.53 |
+21:37:22.7 |
HIP 45272 |
21.80 |
| 2026-06-07 00:00 |
09:14:22.71 |
+21:36:08.4 |
HIP 45272 |
21.87 |
| 2026-06-07 12:00 |
09:14:34.98 |
+21:34:53.9 |
HIP 45272 |
22.38 |
| 2026-06-08 00:00 |
09:14:47.34 |
+21:33:39.0 |
HIP 45272 |
23.31 |
| 2026-06-08 12:00 |
09:14:59.79 |
+21:32:23.8 |
HIP 45473 |
20.85 |
| 2026-06-09 00:00 |
09:15:12.32 |
+21:31:08.3 |
HIP 45473 |
18.02 |
| 2026-06-09 12:00 |
09:15:24.93 |
+21:29:52.5 |
HIP 45473 |
15.31 |
| 2026-06-10 00:00 |
09:15:37.63 |
+21:28:36.4 |
HIP 45473 |
12.82 |
| 2026-06-10 12:00 |
09:15:50.42 |
+21:27:20.0 |
HIP 45473 |
10.72 |
| 2026-06-11 00:00 |
09:16:03.28 |
+21:26:03.3 |
HIP 45473 |
9.28 |
| 2026-06-11 12:00 |
09:16:16.23 |
+21:24:46.2 |
HIP 45473 |
8.88 |
| 2026-06-12 00:00 |
09:16:29.26 |
+21:23:28.9 |
HIP 45473 |
9.65 |
| 2026-06-12 12:00 |
09:16:42.38 |
+21:22:11.4 |
HIP 45473 |
11.38 |
| 2026-06-13 00:00 |
09:16:55.57 |
+21:20:53.5 |
HIP 45473 |
13.72 |
| 2026-06-13 12:00 |
09:17:08.84 |
+21:19:35.3 |
HIP 45473 |
16.43 |
| 2026-06-14 00:00 |
09:17:22.19 |
+21:18:16.8 |
HIP 45473 |
19.36 |
| 2026-06-14 12:00 |
09:17:35.62 |
+21:16:58.1 |
HIP 45473 |
22.44 |
| 2026-06-15 00:00 |
09:17:49.13 |
+21:15:39.1 |
HIP 45473 |
25.61 |
| 2026-06-15 12:00 |
09:18:02.71 |
+21:14:19.8 |
HIP 45671 |
26.67 |
| 2026-06-16 00:00 |
09:18:16.37 |
+21:13:00.2 |
HIP 45671 |
24.61 |
| 2026-06-16 12:00 |
09:18:30.11 |
+21:11:40.4 |
HIP 45671 |
22.89 |
| 2026-06-17 00:00 |
09:18:43.91 |
+21:10:20.3 |
HIP 45671 |
21.58 |
| 2026-06-17 12:00 |
09:18:57.80 |
+21:09:00.0 |
HIP 45671 |
20.79 |
| 2026-06-18 00:00 |
09:19:11.75 |
+21:07:39.3 |
HIP 45671 |
20.57 |
| 2026-06-18 12:00 |
09:19:25.78 |
+21:06:18.4 |
HIP 45671 |
20.95 |
| 2026-06-19 00:00 |
09:19:39.87 |
+21:04:57.2 |
HIP 45671 |
21.92 |
| 2026-06-19 12:00 |
09:19:54.04 |
+21:03:35.8 |
HIP 45671 |
23.41 |
| 2026-06-20 00:00 |
09:20:08.28 |
+21:02:14.2 |
HIP 45671 |
25.33 |
| 2026-06-20 12:00 |
09:20:22.58 |
+21:00:52.3 |
HIP 45671 |
27.60 |
| 2026-06-21 00:00 |
09:20:36.96 |
+20:59:30.2 |
HIP 45747 |
29.90 |
| 2026-06-21 12:00 |
09:20:51.39 |
+20:58:07.8 |
HIP 45747 |
30.41 |
| 2026-06-22 00:00 |
09:21:05.90 |
+20:56:45.2 |
HIP 45747 |
31.34 |